Milling machine control mechanism



March 31, 1953 E. G. ROEHM ETAL MILLING MACHINE CONTROL MECHANISM Original Filed Oct. 5, 1942 4 Sheets-Sheet l Li a W INVENTORS I EfiW/N 6', RUE/IN y HANS FTiITSCH/ III/II/I/I/II/lI/l 4 Sheets-Sheet 2 m mmw a n w March 31, 1953 E. G. ROEHM ETAL MILLING MACHINE CONTROL MECHANISM Original Filed Oct. 3, 1942 Mr Y H E (@WNN NNWJ 9% v Na Q NM, m 0N- 1 m n w iwmmm ampw a 2 n 1 g am W mm J23. sh m v i an a .Q\h. IMNM V llllllllllllllllllllllllllllll II I! Y A S m B n um H u n 3% a I m u u 2% u N29" 3. n n. '1' n AR. m n u m u lll h. {I W] llllllilllillslllllllI! I. IIIIIIIIIIIIIIIIIIIIIIIIIIIII .ll |l|||||||| Ill. A w RV QQY, wwN NW Wm" N; NR v March 31, 1953 E. G. ROEHM ET AL MILLING' MACHINE CONTROL MECHANISM Original Filed Oct. 3, 1942 4 Sheets-sheaf. 3

0 vllllllllfll INVENTOR. f/PU/NG Poi fiH/Ys FQ/Z'Sc W 944% HTT ENEY March 31, 1953 E. G. ROEHM ET AL MILLING MACHINE CONTROL MECHANISM 4 Sheets-Sheet 4 Original Filed 001:. 3, 1942 Patented Mar. 31, 1953 MILLING MACHINE CONTROL MECHANISM Erwin G. RoehmpNorwood, and Hans Fritschl,

Amberley Village, Ohio, assignors to The Cincinnati Milling Machine Co.,Cincinnati, Ohio,

a corporation of Ohio Application July s, 1946, Serial No. 681,854, which is a division of application Serial No. 460,706, October 3, 1942, now Patent No. 2,489,227, dated November 22, 1949. Divided and this application October 15, 1949, Serial No. 121,614

8 Claims.

This invention relates machine tools and more particularly to improvements in milling machines. One of the objects of this invention is to provide in a milling machine a new and improved means for automatically shifting the tool between two difierent positions at predetermined points in the traverse'of the Work support.

Another object of this invention is to provide a new improved mechanism for obtaining rise and fall of the spindle carrier of a milling machine automatically under control of a moving work support.

A further object of the invention is to provide a new and improved mechanismv for effecting axial advance and retraction of a milling machine spindle automatically under control of a moving work support.

derstood that any modifications may be made in the "exact structural details there shown and described, within the scope of the appended claims',without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar parts:

Figure 1 is a right elevation of a machine tool embodying the'principles of this invention.

Figure 2 is-'a" diagram of the hydraulic control circuit for controlling elevation and clamping of the spindle carrier and power means for shifting and clamping the quill.

:Figure' 3 i-sa'. horizontal section with parts broken-away as .viewed on the line 3-3 of Figurewl;

'Figure;..4 is avertical section through a por- Htionot the spindlevcarrieras viewed on the line T41 4 .of-Figure 3..

Figure 3.

Figure 4A is a continuation of Figure 4 iroin line A--A.

Figure 5 is a detail section on the line 5-5 of Figure 6 is a detail section showing the manner oi splining the quill. p

This application is a division of our copending application for milling machines filed in the United tates Patent Ofiice on July 8, 1946, Serial No. 681,854, which is a division of application No. 460,706, filed October 3, 1942, now Patent No. 2,489,227, issued November 22, 1949.

Referring to the drawings, Figure 1 is a right elevation of a machine tool, such as a milling machine, embodying the principles of this invention, and from this figure it will be noted that the machine is of the bed type, comprising a bed [0 upon the top of which is formed guideways l l for supporting a table I2'for power actuated horizontal movement; and an upstanding column or head stock 13 which is integrally connected to the bed and provided with guideways l4 formed on one face thereof for receiving a spindle carrier I5 which is vertically movable with respect to the top of the table [2. The spindle carrier has a quill l6 which is slidably mounted in the carrier for horizontal axial adjustment, and a cutter spindle I1 is journaled within the quill for movement therewith. The spindle may be driven by suitable transmission means not shown, but which may be the same as that shown in parent application, Serial 681,854 supra. The spindle carrier elevating control mechanism is shown diagrammatically in Figure 2. Means are provided whereby the carrier may be vertically adjusted by hand, or alternatively it may be power adjusted automatically under control of the work table where it is desirable to move the cutter into and out of engagement with the work during traverse of the table. The elevating mechanism for effecting the vertical adjustment comprises a cylinder 446 which, as shown in Figure 1, is formed integral with the headstock l3, and this cylinder contains a. piston 441, Figure 2, formed on the end of a piston rod 448, the rodhaving a threaded portion 449 to serve as an elevating screw. This screw passes througha nut 449'. which is anti-friction'ally supported in the carrier for rotation, thefrotation being accomplished by forming bevel gear teeth 450 on one end of the nut for interengagement with an actuating bevel gear 45l attached to the end of a shaft 452. Since carrier moveihandle 456 so that by depressing the plunger 483 against the resistance of spring 484 with one hand, the clamp will be released and the operator may rotate the handle 456 with the other ment is accomplished by rotating the nut, means 5 hand. When this is done the port 48| is conare provided for holding the screw against rotation, and this comprises a pin 453 which extends radially from the piston" rod into; a. longitudinahslot 454 formed in a. fixed'sleeve455.

The sides of the pin may be flattened to prevent by through branch 499 to channel 415.

wear. The shaft 452 extends to the outside :of the carrier as shown in Figures. 1 .and..3.,where it is provided with an operating lever'456.

The carrier I5 is fitllBfI'lll-O..th-8 'guideways l4 nected by the annular groove 485 to a port 481 which is connected by a branch line 488 to chan- .'.nel 411, .and the port "4825 is; interconnected by theannular'groove 486 report 489 and there- Thus, the connections are reversed between the ports '48! 'and-.482-.and .the channels 416 and 411.

Means have also been provided for shifting and-clamping the quill in variou positions, the

y means of three e 45175458;aridifflfifinand -clamping:mechanism being a power actuated means are provided for clamping-the-"carrier by providing a fluid operable clamping member in connection with the gib 459 zbecauserthisg ibsis close to the cutting end ofz thesspindlgcairr-ier.

:rclamp, -and"the-"-; shifting mechanism being so designdthat it'm'ay be operated either by hand ;.or by; power. -.The..power operation is so coupled :thairthe; quill, may be advanced or retracted in The gib 459, as shown inlFigure'.:2,;:-is..adiustedJO m movements of the table.

to a predetermined positiombysa pair ofrclamping nuts 460 which are threaded-on a flxedstud 46! mounted in the carrier. A wedgeeshaped clamping member 462 is slidably mounted in an aperture 463..formed inback of the gib, and this blamping member 'is "operatively connected to -.a.piston 464.133, means of.a tongue'-465"which "fits in a grooveflfidformed in the piston.

One end of the cylinder 461 which containsthe piston464" iS'CUIlIlEClJdibY a'"port opening'468 to ..anced'aaxial ,pressures. on Tlzheicarrier i in. either redirection.

'JI'hese tubularamembers, are .attaIched.-..at ..one siend -.-to ithe ..:bed 'JandJhaVe: a.. sliding connection -1-1xvith the =I-carrier. ..The ..members .412 {413 ';Thequill- 'clamping mechanism comprises a "pair "of"fra'ctional clamping members 49! and 492,- Eigures 2 and 3, which have arcuate surfaces 493 and 494 for? frictionally gripping the periphery ..of ..the.quill. -An. operating rod-495 ..passes through. these. members over. the top.of the quill as shown in'Figure 3, and one. endof the rod.is provided .withawhe'ad 496ffor..exerting a. pull on the. member 49 I. "..The rod. 495, as shown; in; Figure T5,. is n provided ..with :.a ..pinion 491.which. is supported; for free. rotation onthe reduced. end499ofthe. rod. Aflseries of. toggle pins 499 are interposed: between. the.pinion 491 anda. plate.509- which .engages the end of ,the clampingimembers 492. An anti-friction thrust bearing. 5! isinterposed between the pinion and a nut 592 which is threaded on. the end of ..the. clamp. rod-.495 whereby upon rotation of the pinionin.one.direction thev toggle pins are urged- -in av direction :parallel. -to=.the. rod. 495' whereby the members. 49 l and. 492 are: .urged. toward one another to clamp the quill; -and upon rotation in the. other direction the. togglesmembers zare shave-bores formed-imoneend.whichextendpart, orumoved at; an tangles; theaxisvto release the vwayof' the length of these memberswhere they clamping members intersect-crossbores 414' and 415 fordelivering fluid =to :or a-from the chambers. When pressure fist-admitted to the'bore of member 412- and port :468, the-.:piston"464 is :urged upward to effect a; iclamping action, ands'when pressure is admitted --through themember; 413: and port .419,.- thepisf iton's464?;iszmovedrdownwa-rd, =to= efiect --unclampring thespindie' carrier.

lTheztubes 4;Il'hand 413-:are'connected by-chan rnels 4:l6za1id 411 .to ports- 418;;and= 419. ci arewersing yalve indicated;generally-by the 'reference numeral 499. This valve has azpainof ports 48 Band: 482- which may be alternately connect- ..:ed -'to r; pressures and 1 exhaust. plunger't483 which isw normally held in thepo- "fSitiOIT ShOWII byi afspring' 484-.whereby. the; port 48 I i-is 'zconnected' to :.:port 418 a and port 482 is connected to portxz419tby :the annular grooves -485 anda486 respectively.

lt will-beobviousthat if the.p'0rt.48l. is connected topressure: by means to be described and the p'ort482. is connected to: exhaust that the' piston 464 'wi1l' be actuated: in a; direction to-clamp the carrier.

This valvehas' :been provided .to'. make it pos- 'sible" "for the-operator to release theclamp dur- '*ing'"=m'anu'a1'-= actuation of the elevating mechamism. -"The Waive is mounted in the :bed in; convenient relation to the -"-'e1ev'ating 1 operatin The valve has a. 6

, a: spring 5| forinterconnecting channels 5|2 and m with enemies 5m 'and:508. When the .plunger 5| 0 :is movedagainst the resistance of the spring 5!! these connections.are-reversed, thereby releasing the clamp.

The "q'uillis held-against rotation by a pin-5M which,' as; shown in Figure 6, is-mounted in fthe ..wall of the carrier and has flattened ends which -.project into a,slot'=5l5 form-ed longitudinally of the quill. The elongated slot permits maxial :imovement ofithepouill. '.:This axial movement is accomplished 'by; cutting a ipartial rnut thread 5H5 in the un'dersurface of the quill as shown in -Figures? 3iand. 4xand"providing a-rotatable screw 5' 5 I 1 meshiwith theinutthread. which produces the ultimate efiect of a. schew-and nut. 'The .529. end of the shaft for clamping the shaft to the screw 511 is held against axial movement whereby rotation of the screw will effect axial movement "of the quill. The screw is fastened to a shaft5l8 to which is also attached a pinion 519.

The pinion meshes with a screw thread 520 formed on a piston rod 52l which terminates in a piston 522 that is slidably mounted in a cylinder 523 formed in the carrier. The piston has an'axial splinder bore'524 in which fits a splined stud 525.

The stud 525 is "formed integral with the cylinder head 526, the cylinder head being attached to the cylinder by bolts 521. The cylinder head also has integrally'formed therewith a stud shaft t 528 which is journaled in anti-friction bearings A nut .530, Figure 4A, is. threaded on the inner race of the hearing. The outer race of the bearing is clamped in a recess .53l formed in the ,wall 532 by a cap 533. This construction holds the cylinder against axial movement while permitting rotation thereof, the cylinder being rotatable in bore 534.

' In order to impart rotation to the cylinder one end of it has a gear 535 integrally formed therewith and this gear intermeshes with a pin- .ion 536 which is attached to the end of a shaft this thread will impart rotation to the gear 5l9,

and. thereby through the screw and nut connection 5| 1, 5l6, the quill will he moved axially. Power shifting of the quill is obtained by reciprocating the. piston 522 in the cylinder 523 whereby the thread 520then acts as a rack to impart rotation to the pinion 519.

Referring to Figure 2, fluid pressure is supplied to the quill clamping piston 503 and the quill actuatingpiston 522 from a pair of lines 539 and H2. These channels are in the carrier and since the source of pressure is outside of the carrier they are connected by a pair of sliding trombone connections 54!, and 542 to channels 543 and 544. which are located in the bed.-

The normal operating position of the quill is its advanced position which is effected by the piston 522 when at the right hand end of the cylinder 523, as shown in Figure 2, and the quill is clamped. This is the position utilized for cutting.

a When the quill is to be retracted the connections are such that the quill is unolamped by the piston 503 and sequentially retracted by the piston 522. For advancementof the quill, the piston 522 .is actuated first, and then the piston 503 is sequentially actuated to effect the clamping. This is automatically accomplished by providing a .pair of delay valves 545 and 546, the valve 545 serving to delay the advance of piston 522 until the unclamping has been accomplished and the valve 545 serving to delay the clamping action until the piston 522 has completed its advancing I explained first. This is accomplished by connecting the channel 5l2 to pressure and the channel 539' to exhaust. The pressure in channel 512 flows directly through the reversing valve 509 to port 541 oi? cylinder '504 which will cause the piston 503 to move in a direction to unclamp the quill. Y

The channel 5l2 has a branch connection 540 to port 548 of the delay valve;545. The valve plunger 549 is normally held in the position shown by a spring 550. The plunger has an annular groove 55! in which is formed an interdrilled passage 552 that communicates with the vend of the 'valvewhereby pressure may be built up to shift theplunger 549 against the resistance of spring 550. This spring is strong enough to hold the valve in the position shown and again'st the pressure necessary to effect unclamping.

, After the unclamping has been accomplished, the pressure increases, overcoming theresistance of spring 559 and shifting the plunger 549 sumciently for the annular groove 551 to interconnect the port 546 with port 553. This port is connected by channel 554 to port 555 located in the forward end of the cylinder 523. The quill being unclamped, this permits the pressure to shift the piston 522 to the other end of the cylinder; The port 556 at the other end of the cylinder'523, it will be noted, is connected directly to channel 539 which is a reservoir channel, thereby permitting the free escape of fluid.

The fluid escaping from the end of the clamping cylinder 504 through the port 551 passes through channel 598 and the reversing valve 509 to channel 513. It will benoted that this channel terminates in a port 558 of delay valve 546. This valve has an annular groove 559 which permits the oil to continue to a check valve 560 which is .forced open by the escaping fluid whereby the this being necessary because the check valve 560will close due to the direction of flow of the liquid. The plunger 564 of this valve is normally held in the position shown by a spring 565 but is provided with an annular groove 561 and an interdrilled passage 568 whereby the fluid may pass to the chamber 569 and effect shifting of the plunger to effect interconnection of port 563 with port 558. The fluid will then continue through channel 513, valve 509 and channel 50 to effect clamping of the quill.

A pair of channels 510 and 51! serve to control hydraulic operation and hydraulic clamping of the carrier in the same manner that the quill was controlled in the sense that the normal operating position of the carrier is its lower position with the piston 441 at the bottom of the cylinder 446 and the carrier clamped. The carrier is elevated by first unclamping it and ,then actuating the piston 441 upward which moves the carrier toan upper unolamped position. Upon reversing the connections to channels 510 and 511 the carrier is moved down and then clamped. The delayoperation of the carrier and the clamp is accomplished by providing a pair of delay valves 512 and 513 having plungers 514 and 515 which are gnormallxizheldsingin erpo ition shown-shy spr n g-pluneerfilhandshift-th sam a ainst ther Y sistaneec spri ia.516. .,--.'12 .;eff..e.ctsinterconn ct o port. fill-with,- ort. 5.8 I whereby. theil way. continue.th-rous c ann etoth l wer @111 Wlindeu 445.:causi-ngupwardrm vementof the; -piston- 441. The, fluid .exhaustingjfromjhe .,upper-;,end-of the cylinder: 446 passes through the channe1.- 0-idirect to servoir- Th fluid e u-haustin fr m th upp r en of the ampin cylinder passes through channel. 416,; the reversi g valveAall and-channel583 tothe checkvalve a5ii4aw-hich is so positionedas to openiorthis ;;direction of fluid-now so that the fluid .will, conltinue, to, channel .510, and, thereby .to exhaust.

Upon reversal oftheconnections fluidpressure flowsv through channel. 510, immediately. causing downward movementof the piston, 441,. and the-n r-as .the pressure rises it iscommunicated to port r.585-of delayvalve-513. This valve is connected ,through; the annular groove 566 and, the interdrilled passage 581Htochamber, 589. The rise in pressure in chamber 568.- shifts. the. plunger, 515 againsti the resistance of spring..516v and interconnectsthe:port 585,.withport 589 whereby the theme-m y; c ntinue thr u h. channel 583 .to th olampingcyhn er th r by mpin he. carrier after it has completed its movement.

Malt will, ;now ,,be ,seen that thereris pair of channelsl543 ,and.544. which, control fluid operai.0n,.of thenuill an t c p n -m ni m. andianotherpair of 'channelsj51ll and51I which -control hydraulic actuation of the carrier and its clamping mechanism.

',.These four channels are connected to a selector valve 599 which serves to connect either one pair or the other of these channels to a trip controlled valve 59I, and at the same time maintain :a pressure connection to the proper one of the otherpair ofchannels which will'hold the particular mechanismin its normal clamped polnsition. "For convenience of explanation, *the selector '--valve*590' is shown-in sections in' Figurelaand these sections have been numbered consecutively -fromi.592.-.to 591. The channel 543 isconnected to port 598 of section,593;gthe channel 544 is .rconnected toportf 599 ,of section 596; the channel t51llg-isconnected to port 606 of section 593" and .the channel-25H is connected to-port66l of secmien- 596. {This valve has a rotatable; plunger 602 *to w-hichisattached an operating. knob 663 :uwhich =.:has three positions indicated .by the :arrows 604,. 605, and-.606.

Pressure is supplied fonoperating. these devices ,.,by.a pump. 661.. which .has a deliverychannel 668 which isconnected to 130111.609 of section, 5.92. of ,the .selector-valve. This pump has anintake 610 through whichfluidis withdrawn froma reservoir 6| I through a.su itable'filter 6I2. Foremerenpwpurposes achelck v ve. 61 may. be int r- F posed between the channels 608 and. 6| 6. The

wt tctonvalve issh wn i its .o finos t he eby the fluidentering M609 flows intotheannular grooveti 4 of section 592 and thereby to thearcu- 'ate. grooves '6I5. and .6I6 of, section 593, these grooves forming part oftheannular groove.

Fromthis it. will be seen that the pressure is connected .to .bothchanne lsl543 and 516, the .formerleading to. the quill mechanism to hold it initsclamped pos t and the latte xtendin to the carrier mechanism to hold it in its clamped position. .The return channels are. connected to arcuate grooves 6 I1and'i6l8 of. section 596 which 5 directly communicate with .the annular groove 6] 9'. in. sectionj591. The port.6 20 connectsthis -.sro v .t e t rn chann l .62' w er b flu ,may; returnto the reservoir .61 I.

Wh n. theselecto va v pl n er is rota ed: i a counterclockwise.,direction to the position 694 .whicbimisn a t oqu p ii om e or [669.is still in communication withthe arcuate groove ,66 but the port 598 is connected to, a longitudinally extending groove 622. vThis groove intersects an annular groove fi23 in section-594 which has, a port 6 24, connected by channel 625 to port .526 of the trip controlled valve 59I. Similarly, the port Bill in section 596'remains .connected to the exhaust groove 6I8but the port 599 becomes connected to a longitudinally extending groove 621 which intersects annular groove 628 in section 595. This annular groove is connected by port 629-and channel 636 to port 63I of the tri controlled valve.

Itwill now be seen thatupon'rotation of the selector valve plunger 692 to the quill position that the same connections are maintained to the carrier channels-516 and 5'II while the quill control channels 543-and 544 are connected through the selector valve to the trip controlled valve 59 I. The trip controlled valve has arotatable plunger 632 to the reduced end of which is attached an operating lever 633. This lever is semi-circular in shape to provide a surface 634 for engagement by a trip plunger 635, a surface 636 which is engageable by a trip plunger631 and a lug'638 which engages a slot in a manual control plunger 639. The plunger, of course, is adapted to move the valve to either one of two positions, while the trip plunger'635 effects counterclockwise rotation of the valve and the trip plunger 631 effects clockwise rotation of the valve.

This trip valve is located in the bed of the machine adjacent to the carrier side of the table, and the table is provided with a dog carrying T-slot 649 in which suitable trip dogs 64I are adjustably mounted.

- The trip valve is shown in three sections, the section 642 having a pressureport'643 which is supplied by line 668; and a section 644 which has an exhaust port .645 that is connected to the return channel 62L The section 642 has an annular groove-646 which is intersected by a pair of axial extending grooves 641 and 648 that terminate in section 632. In section 644, the plunger 632 is provided with another annular groove 649 which has 'four axial extending grooves 656 that also terminate in section 632 whereby the two pressure'grooves are flanked by a pair of exhaust grooves. It will now be apparent that upon rotation of the valve 632 in a clockwise direction that port 626 will be con- -nected to pressure, and port 63l will be con- 1 nected to exhaust.

Thus, the trip valve serves as a reversing valve to alternately connect the'channels 525 and 630 to ressure and reservoir. Then, dependingupon "9 the position of the selector valve, these two channels may be connected to either the pair of channels which control operation of the quill, or the pair of channels which control the operation of the carrier.

There has thus been provided a new and improved mechanism for automatically positioning thespindle of a milling machine'either axially or laterally' fromone position toanother in-synchronization with the movements of a work table. This makes possible automatic cycling of a millmg machine whereby the work table may be traversed'to a start cutting position at whi h the spindle" i's'sh'ifted from an inoperative to an operative position so that continued movement of the table will efiect a machining operation, at

the end of which the spindle is returned to its inoperative position, so that upon return movement of the work table there will be no rubbing contact between the cutter and the work. It will be understood that the axial shifting movement is more useful when end mills are attached to the spindle and that lateral shifting will be used with circular cutters. It will also be apparent that this mechanism may be used for intermittent cutting in two difierent planes when after machining in one plane, the cutter is shifted for machining in a second plane.

What is claimed is:

1. In a milling machine having a reciprocable table, a rotatable tool spindle and a spindle carrier for supporting said spindle for movement toward and from the table, the combination of fluid operable means for shifting said carrier between a non-working position and a working position, fluid operable means for clamping said carrier in its working position, a control valve supported for trip operation by the table, a pair of control channels, a source of pressure, means operable by the valve for alternately connecting said source of pressure to said channels, one of said channels being directly connected to the fluid operable means for the carrier, the other channel being directly connected to the fluid operable clamping means, and delay valve and check valve means cross-connecting said channels to the other fluid operable means whereby when one of said channels is under pressure the spindle carrier will be moved first and then clamped, and when the other channel is under pressure the clamping means will be unclamped first and then the carrier moved.

2. Inamilling machine having a reciprocating table, a carrier, a rotatable tool spindle, a quill for supporting said spindle in the carrier for movement relative to the table, the combination of fluid operable means for shifting said quill from a non-working position to a working position, fluid operable means for clamping said quill, a control valve supported for trip operation by the table, a pair of control channels, a source of pressure, means operable by the valve for alternately connecting said source of pressure to said channels, one of said channels being directly connected to one of said fluid operable means, the other channel being directly connected to the other fluid operable means, and delay and check valve means cross-connecting said channels to the opposite fluid operable means whereby when one of said channels is under pressure the spindle quill will be moved first and then clamped, and

' -10 movement, the combination of separate fluid operable means for efiecting the respective move ments, a reversing valve supported for trip opera tion by said work support, and means to selectively connect said valve to either of said fluid operable means.

4. In a milling machine having a reciprocable work supportingtable, and a spindlecarrier, the combination of fluid operable meansfor shifting said carrier between a working position and a non-working position, a quill mounted in said carrier and having means for rotatably supporting a spindle, fluid operable means for shifting said quill between, a working position and a non {working position, a source of pressure, and a con-. trol valve havinga position for simultaneously connecting saidsourc'e-of pressure to both of's'aid fluid operable meaiis'in a manner to move and hold"both' the quillland the carrier in their respective working positions.

5. In a milling machine having a reciprocable work supporting table, and a spindle carrier, the combination of fluid operable means for-shifting said carrier between a working position and a non-working position, a quill mounted in said carrier and having means for rotatably supporting a spindle, fluid operable means for shifting said quill between a working position and a nonworking position, a source of pressure, a control valve having a position for simultaneously connecting said source of pressure to both of said fluid operable means in a manner to move and hold both the quill and the carrier in their re spective Working positions, a trip operated control valve, and means to alternately position the firstnamed valve for selectively connecting either oi said fluid operable means to said trip controlled valve while still maintaining pressure on the other fluid operable means.

6. In a milling machine having a reciprocating table, a rotatable tool spindle, and a carrier for supporting said spindle for relative movement with respect to said table, the combination of fluid operable means for shifting said carrier between a working and a non-working position, manually operable means for adjusting said carrier while in either position, fluid operable means for clamping said'carrier, a source of pressure, a control valve, a pair of control channels alternately connectible by said valve to said source of pressure whereby one of said channels is always under pressure, means connecting said channels in parallel to said fluid operable means for joint control by said valve, and separate means for reversing the connections between said channels and said fluid operable clamping means whereby said clamping means may be released for manual adjustment of said carrier.

'7. In a milling machine having a reciprocating table, a rotatable tool spindle, and a carrier for supporting said spindle for relative movement with respect to said table, the combination of fluid operable means for shifting said carrier between a working and a non-working position, a pair of control channels for said fluid operable means, fluid operable means for clamping said carrier, a second pair of control channels therefor, a source of pressure, a control valve having a pair of channels connected in parallel to the respective pairs of first-named channels, a delay valve interposed in one of said connections for delaying operation of said clamping means until the spindle carrier has moved to a working position, and a second delay valve interposed in the other connections for delaying movement of the,

a eaoei 11 spindle carrier to a non-working position until the unclamping means have been actuated.

8. In a milling machine having a bed, a table reciprocably mounted on said bed, a spindle carrier supported for movement toward and from the table, a quill reciprocably mounted within the carrier and having a tool spindle rotatably journalled therein and movable therewith, fluid operable means for shifting said quill including a piston and piston rod, said piston rod having a screw thread formed thereon, a spiral gear intermeshing with said thread, means to admit pressure to said piston for power shifting of said quill, and manually operable means for rotating said piston rod to efifect manual adjustment of said quill while said piston is under pressure.

ERWIN G. ROEHM. HANS FRIT'SCI-II.

1 2 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,763,142 Ernst June 10, 1930 1,976,108 Archea Oct. 9, 1934 1,978,360 Archea Oct, 23. 1934 2,012,249 Sassen Aug. "20, 1935 2,293,880 Armitage et a1. Aug. 25, 1942 2,356,796 Purvin Aug. '29, 1944 2,368,061 Wortendyke Jan. 23, 1945 

